巴斯夫催化剂(上海)有限公司技术交流文件

Catalysts Application
Introduction
Michael Cheng
Eddie lin
Aug. 26, 2008
Part 1
TWC Fundamentals Introduction
三效催化剂的组成
TWC Components
载体Substrate
涂层Washcoat
氧化铝Alumina
储氧材料Oxygen storage Component 助剂Promoters and stabilizers
贵金属Precious Metal
Pt, Pd and Rh
载体Substrates
陶瓷Ceramic
z堇青石Cordierite
–2MgO-2Al
2O
3
-5SiO
2
–热稳定性Thermal Stability > 1300o C 金属Metallic
z铁铬合金Fe-cr alloy
–Fe, Cr, Al
–Y and/or Ce added
–热稳定性Thermal Stability < 1300o C
整体式载体Monolithic Substrates
Close-up view of
metallic monolith
Ceramic monolith substrates
Ceramic foam
Metal monolith
三效催化剂的工作环境
Operating Conditions of TWC
温度Temperature
¾冷启动时，每分钟300o C的加热速率Heat-up rates of 300o C per minute occur during cold-start
¾即使在热车时，加速和减速也会引起每分钟正负100o C的变化
Even after warm-up, changes of ±100o C per minute are caused by vehicle acceleration & deceleration conditions
¾排气温度可以高达900o C The temperature of exhaust gas can reach 900o C 气体成分Gas Composition
¾在加速状态（强还原）和减速状态（强氧化）下不停地转换Constantly shifts between acceleration mode (strongly reducing) and deceleration
mode (strongly oxidizing)
¾“波动”气流，这是三元催化剂工作的基本原则，引起频繁的氧化还原变化“Perturbated”flow, which is fundamental to TWC operation, causes
second-to-second redox changes
三效催化剂中贵金属的功能
Precious Metal Function in TWC
氧化剂Oxidants:
O 2, NO x 还原剂Reductants:HC, CO, and H 2
¾在任何时候都有可能有过量的O 2, NO x 或HC, CO 和H 2At any moment, there may be excess of O 2, NO x or HC, CO, and H 2
¾Pt 和Pd 是很好的HC 和CO 氧化催化剂
Pt and Pd are good oxidation catalysts
¾Rh 是好的NO 还原催化剂
Rh is a good NO reduction catalyst
三元催化剂的贵金属系统
Precious Metal Systems for TWC Catalysts
Pt/Rh 传统。

对燃油中的硫中毒有最好抵抗力。

Traditional. Most resistant PM to
fuel sulfur/poisons.
Pt -好的氧化作用。

生成一些NH 3。

Good oxidation. Some NH 3formation.
Rh –极好的NO x 还原作用。

高温下易与Al 2O 3反应丧失活性。

Excellent NO x reduction. Reacts with Al 2O 3 during high temperature exposure to lose activity. Pd/Rh 因为更清洁的燃油而新近推出的。

Recent introduction due to cleaner fuels.
分层涂敷用来避免形成合金。

Washcoat layering used to avoid alloying.
Pt/Pd/Rh 高含量Pd 与Rh 和Pt 的分离涂敷有高温稳定性和好的HC 活性。

High Pd
loading segregated from Rh and Pt yields high thermal stability and better HC activity.
Rh and Pt 加上金属氧化物改善Rh 和NO x 反应的热稳定性。

Rh & Pt plus
Metal Oxides improve thermal stability of the Rh NO x reaction
Pd Only 高温位置有卓越的去除包括NO 污染物的整体性能。

High temperature
locations yield excellent overall performance including NO x
使原子级的催化剂工程技术得以实现
5 nm
结论Conclusions
三效催化剂必须同时进行氧化反应和还原反应TWC must
simultaneously do oxidation and reduction chemistries
三效催化剂必须应对苛刻且多变的应用环境TWC must cope with rapid changes in condition
三元催化剂中贵金属的选择取决于其应用Selection of Precious Metals for TWC Catalysts Depends on the Application:
排放法规Emissions Regulation
燃油控制系统Fuel Control System
燃油品质Quality of Fuel
三元催化剂中贵金属的功能Precious Metal Function in TWC Catalyst:
Pt, Pd 氧化Oxidizing
Rh NO 还原NO Reduction
单Pd多用于紧藕合催化剂设计Pd for Special Close Mounted Catalyst Designs
BASF公司专有的涂层技术提供卓越的催化活性和耐久性BASF’s Proprietary Washcoat Technology Provides Superior Catalytic Activity and Durability
Part 2
TWC Proposal Design
载体目数对床温的影响
High Cell Density Provides Faster
Temperature Rise During Cold-Start
SAE Paper# 982634 Corning et.al.
载体规格对背压的影响
Pressure Drop as a Function of Flow
载体目数对排放性能的影响
Test Results Show Benefits with 600 & 900 cpsi Substrates
Substrate (cpsi/mil)
Substrate Wt. Reduction GSA NMHC Engine-Out NMHC Tailpipe
400/6.5 0 27.3
1.726 0.103
600/3 21 35.3 1.674 0.073 900/2 28 43.7 1.716 0.060 1200/2 25
50.8
1.754 0.062
Catalysts Oven-aged @ 1050°C
FTP Tests on Nissan altima; Cats in Close-Coupled Position
SAE 1999-01-0271
Example 1
催化剂体积设计
Catalysts Volume Determination
Average Catalyst volume/Engine volume for E 4 application
0.987 (max 1.33, min 0.53)
贵金属配方设计
PM loading and ratio design
贵金属配方设计依赖于载体方案It depends on the substrate proposal;
贵金属配方设计依赖于催化剂的布局It depends on the layout of TWC;
贵金属配方设计依赖于原机排放数据It depends on the emission data of engine out;
钯的用量取决于THC的原机排放和入口温度控制Pd loading is determined with the emission data of THC_EO and inlet
temperature control;
铑的配方取决于lambda控制Rh loading is determined with the lambda control.
Part 3
BASF TWC development from Euro IV to Euro V
1,2
区域政治法规的要求驱动BASF 的研究
Background: Research at BASF Is Driven by Legislative and Geopolitical Issues
欧V HC/NO x 排放限值比欧IV 低25% Euro-V HC/NO x emissions limits 25% lower than Euro-IV 京都协定要求更好的燃油经济性Kyoto accord mandates higher fuel economy 需要应对贵金属价格的高波动High PM Price fluctuation needs to be addressed 下列因素对催化剂的研究造成直接影响These factors directly impact catalyst development needs z 为了快速起燃紧耦合催化剂是必需的Close-coupled catalysts are
required for fast light-off z 减少燃油加浓意味着更高的老化温度Reduction (or elimination) of fuel
enrichment means higher aging temperatures z 贵金属的效率需要进一步提高PM Effectiveness needs to be Improved
满足欧V排放的设计要点
Design Considerations for Meeting EU V 紧耦合催化剂的布置Close-Coupled Catalyst Locations: System Design
控制策略优化Improved Control Strategies
z激进的冷启动Aggressive Cold-Starts (400o C Within ~ 50 Seconds)
z减少空燃比的瞬变Calibrations That Reduce A/F Transients
载体优化Improved Substrates
z高孔目/薄壁High Cell Density/Thin Wall
催化剂优化Improved Catalysts
z涂层的热稳定性Wash coat Thermal Stability
z涂层设计Wash coat design
Example 1
800
0.25
BASF致力于高性能催化剂的研究
BASF is Focused on High Performance
Catalyst Research
新型高温稳定载体材料有助于改善贵金属经苛刻老化后的分散度New, high-temperature-stable supports to maintain PM dispersion after severe aging.
高耐久的储放氧材料可以保证低的CO/NOx排放High-durability OSC components to provide low CO/NOx emissions
高性能的助剂可以抑制贵金属的烧结High-performance promoters to reduce PM sintering
优化涂层结构Optimized Washcoat layering strategies z贵金属和储放氧材料的布置PM and OSC locations (segregation) z涂层的负载Wash coat loading
80% BET
80%
BET
12 hrs w/ 10% Steam
Advanced Materials Improve Overall
Performance of Catalyst
Objective is to improve catalyst’s overall performance with advanced materials.
Selected Technologies
z Euro IV serial technology
z Euro V development sample (New (i) WC design, (ii) BMO, (iii) OSC material, and (iv) promotors)
Loading 40g/ft³, 0:9:1, 4,66x5, 400/4
Aging cycle: oven aging 4h 1200o C(hydrothermal)
DP cold flow measurements
MVEG 2,0 TFSI 4cyl Vehicle
Euro V Application Study on 1.8L vehicle with Euro IV calibration (Fresh Catalyst)
Euro V Catalyst z CCC: PM loading 80 g/ft3 higher than Euro IV z UFC: PM loading same with Euro IV z
New catalyst formulation
EUV THC
EUV NMHC
EUV NOx
0.57L 600/4
1.1L 400/6
CCC
UFC
Flow direction
New Advanced Technology Catalyst get fast light-off performance
PM Loading Optimization: New Advanced Fresh Catalyst Meet 40% THC Emission Target of Euro V
Standard Achieved with Large Margin
Standard Achieved with Large Margin。